1. Field of the Invention
The present invention relates to a bonding method and device for bonding a film to an object to be welded.
2. Description of the Related Art
In general, a liquid medicine, a powder medicine, food, powder (sugar or the like) which is weak to humidity, an inspection chip which detects specific gas, and the like are packaged in a packaging container. As a kind of such a packaging container, for example, a transfusion bag filled with a transfusion containing sugar, an electrolyte, amino acids, vitamins, or the like is well known. A transfusion bag is formed of a resin film (plastic film) or the like in view of good handling properties, being lightweight, reduction in volume of waste, or the like.
The resin film used as a material of the transfusion bag has low gas barrier properties since an additive, which improves gas barrier properties, is used in an additive-free manner in order to prevent such an additive from being injected into a human body after being eluted in the transfusion. Here, it is easy for liquid medicines, such as sugar, amino acids, or an electrolyte, with which the transfusion bag is filled to significantly deteriorate due to entering of oxygen. Therefore, if the transfusion bag is left to stand in the air, the liquid medicine deteriorates due to oxygen in the air transmitted through the transfusion bag.
In a transfusion bag disclosed in JP1999-56970A (JP-H11-56970A), a periphery portion of a protection sheet is bonded to a periphery portion of a front surface of a bag main body formed of a resin film or the like, and a periphery portion of a cover sheet is bonded to a periphery portion of a rear surface of the bag main body. The protection sheet or the cover sheet includes a function layer having gas barrier properties, and therefore, the gas barrier properties of the transfusion bag are secured. The periphery portion of the protection sheet or the cover sheet is bonded to the bag main body by performing heating and pressing using a pressurization mold which has a pressurization surface with a frame shape corresponding to the shape of the periphery portion.
In a transfusion bag disclosed in JP1999-348171A (JP-H11-348171A), similarly to JP1999-56970A (JP-H11-56970A), gas barrier properties are secured by thermally welding a periphery portion of a gas barrier film, which has a gas barrier function layer, to periphery portions of both surfaces of the bag main body formed of a resin film or the like.
In JP2004-231199A, gas barrier properties of a transfusion bag are secured by storing the transfusion bag formed of a resin film or the like in a transfusion bag-storing external packaging bag with gas barrier properties.